Exposure to toxic agents, and especially CW agents, and related toxins, is a potential hazard to the armed forces and to civilian populations, since CW agents are stockpiled by several nations, and other nations and groups actively seek to acquire these materials. Some commonly known CW agents are bis-(2-chloroethyl) sulfide (HD or mustard gas), pinacolyl methylphosphonofluoridate (GD) and 0-ethyl S-(2-diisopropylamino)ethyl methylphosphonothioate (VX), as well as analogs and derivatives of these agents. More generally, these types of chemical warfare agents are referred to as H, G, and V type agents. These CW agents are generally delivered as fine aerosol mists which, aside from presenting an inhalation threat, will deposit on surfaces of military equipment and hardware, including uniforms, weapons, vehicles, vans, and shelters. Once such equipment and hardware is contaminated with one of the previously mentioned highly toxic agents, the agent must be removed in order to minimize contact hazards.
For this reason, there is an acute need to develop and improve technology for decontamination of highly toxic materials. This is especially true for the class of toxic agents known as nerve agents or nerve gases which are produced and stockpiled for both industrial use and as CW agents. Simply by way of example, one class of nerve agents with a high level of potential lethality is the class that includes organophosphorus-based (“OP”) compounds, such as the G-agents Sarin and Soman, and the V-agent VX. Such agents can be absorbed through inhalation and/or through the skin of an animal or person. The organophosphorus-type (“OP”) CW materials typically manifest their lethal effects against animals and people by inhibiting acetylcholineseterase (“AChE”) enzyme at neuromuscular junctions between nerve endings and muscle tissue to produce an excessive buildup of the neurotransmitter acetylcholine, in an animal or person. This can result in paralysis and death in a short time.
In addition to the concerns about CW agents, there is also a growing need in the industry for decontamination of industrial chemicals and/or insecticides, for example, ACHE-inhibiting pesticides such as parathion, paraoxon and malathion, among others. Thus, it is very important to be able to effectively detoxify a broad spectrum of toxic agents, including, but not limited to, organophosphorus-type compounds, from contaminated surfaces and sensitive equipment.
One decontamination material used by the U.S. Army, is XE555 resin (Ambergard™ Rohm & Haas Company, Philadelphia, Pa.). XE555 is presently being used by the military for immediate decontamination applications. The objective of immediate decontamination operations is to remove toxic agents from the contaminated surface as rapidly as possible. However, XE555 has several disadvantages. Although effective at removing chemical agents, XE555 does not possess sufficient reactive properties to neutralize the toxic agent(s) picked up by this resin. Thus, after use for decontamination purposes, XE555 itself presents an ongoing threat from off-gassing toxins and/or vapors mixed with the resin. In addition, XE555 is relatively expensive in the quantities required for decontamination purposes. Other reactive sorbents used by the army are “A-200”, an alumina-based material used in the M100 Sorbent Decontamination System. Although both of these solid-phase decontaminates are able to quickly remove CW agents from surfaces, they suffer from slow reactions with CW agents such as GD, HD, and VX (compared to typical liquid-phase decontaminants). Thus the contaminated sorbents present a persistent hazard themselves following their use. This is particularly true for VX, the most persistent and toxic of these agents. Clearly, improved sorbents are required to eliminate this potential secondary contamination hazard present by current, conventional sorbents following their use.